A key fob is a generally decorative and/or at times useful item people often carry with their keys, on a ring or a chain. Key fobs are often called “key rings” or “key chains” in colloquial usage. Fobs vary considerably in size, style and functionality. Most commonly they are simple discs of smooth metal or plastic, typically with a message or symbol such as that of a logo or a sign of an important group affiliation. A fob may be symbolic or strictly aesthetic, but it can also be a small tool. Many fobs are small flashlights, compasses, calculators, penknives, discount cards, bottle openers, and USB flash drives, to name a few. As electronic technology continues to become smaller and cheaper, miniature key-fob versions of (previously) larger devices are becoming common, such as digital photo frames and simple video games.
Electronic key fobs are used for activating such things as remote keyless entry systems on motor vehicles. Early electric key fobs operated using infrared and required a clear line-of-sight to function. More recent models use challenge-response authentication over radio frequency, making them harder to copy and eliminating the need for line-of-sight communication.
Key fobs are increasingly used in apartment buildings and condominium buildings for access to common areas (i.e., lobby doors, storage areas, fitness room, pool) and in office buildings. These types of fobs usually contain a passive RFID tag. The fob operates in much the same manner as a proximity card to communicate (via a reader pad) with a central server for the building, which can be programmed to allow access only to those areas in which the tenant or owner is permitted to access, or only within certain time frames.
Telecommuters may also use an electronic device in the form of a key fob that provides one part of a three way match to log in over an unsecure network connection to a secure network. This kind of key fob may have a keypad on which the user enters a PIN in order to retrieve an access code, or it could be a display-only device such as a VPN token that algorithmically generates security codes as part of a challenge/response authentication system.
Another example of a fob is the credit card fob, such as the PAYPASS® fob available from MasterCard International Inc. This type of fob uses a hidden embedded computer chip and radio frequency antennae. The user taps the fob at a special checkout terminal, and payment details (e.g., credit card number) are sent wirelessly from the fob to the terminal for use in the MasterCard network. The fob must be very close (in the order of inches) from the terminal in order to operate with the system.
While fobs for credit card applications have gained in popularity in recent years, there is still some resistance among consumers to using these types of fobs. One primary reason for this hesitancy is the perception that the fobs are not secure. For example, if one were to lose their keys, the fob could be used for purchases by another prior to reporting the fob as lost.
Therefore, improved, more secure fobs for use in secure transactions are desired.